An image watermarking scheme using non-tensor wavelets

Watermarking plays a significant role in copyright protection. In this paper, a new method of digital watermarking is proposed based on a new non-tensor bivariate wavelet filter banks with linear phase, which are constructed from the centrally symmetric matrices. Our investigation demonstrates that the constructed non-tensor product bivariate wavelet filters have the following desirable properties, namely, its corresponding wavelet transform can detect more singularities of the host image with reflecting whole orientation while only three orientations being considered by traditional discrete separable transform(DWT). For this reason, details are given more in middle and high frequency, the imperceptible and robust requirements of watermarks are fulfilled and optimized. Some experiments with detailed comparisons with DWT are carried out. Experiments are conducted and positive results are achieved, which show that the proposed watermarking scheme is applicable to the gray image, and the watermark is robust against noise, compression, scaling, cropping and sharpening.